Hey “I understand that you are going to Japan as an expatriate and planning to enroll in an international school. How may I assist you? I am here to provide any help or guidance you may need.”
I had the same experience. I went to Vietnam for a year because of work, and I sent my children to an international school at that time. My children said they gained confidence in their English thanks to that period back then, so I thought I had a good time too.